The submarine’s body may be constructed from drainage pipes and the hatch from a recycled skylight, but according to its 18-year-old inventor, this single-person U-boat can plunge to a depth of 30 feet and has already completed three successful dives, CNN reports. The Nautilus took high school inventor Justin Beckerman just six months and $2,000 to put together — all while keeping on top of his homework. The submarine has ballast tanks to maintain its depth and equilibrium; air vents that bring oxygen down from the surface; a functioning PA and a range of emergency systems including back-up batteries, a siren, strobe lights, a breathing apparatus and a pump to fight leaks…